This study investigated the extent to which the notion of knowledge about alternative conceptions is featured in the curriculum for pedagogy courses of a pre-service science teacher programme and explored pre-service students' understanding of the notion having completed the pedagogy courses. This was achieved by analysing three curricula, one each for physics, biology and chemistry pedagogy courses and by interviewing 29 pre-service teachers from one university in Tanzania. The study was guided by a framework of five aspects of the notion of knowledge about alternative conceptions, which were adapted from Gomez-Zwiep. These are the definition of alternative conceptions, their nature and origins, examples of alternative conceptions in science, their impacts, and instructional strategies to address alternative conceptions. The results indicated that the notion of knowledge about alternative conceptions is generally not featured in pedagogy courses. Further, although most of the pre-service teachers could identify the impacts of alternative conceptions on students' learning, they had a limited understanding of the notion. Thus, the study recommends that pedagogy courses should emphasise explicit instruction of the notion of knowledge about alternative conceptions. Further, pre-service teachers should be exposed to the debate about how to approach good instruction in relation to alternative conceptions.